Carica papaya is an eminent medicinal plant used all over the world to treat several diseases like malaria, dengue, inflammation, and skin infections. In this study, preliminary phytochemical screening for C. papaya flowers was carried out using different methods as TLC screening and UV-spectroscopy along with evaluation of antioxidant and antibacterial activities. Methods were also developed for TLC and UV-visible spectroscopic analysis of the extracts. Results of phytochemical screening revealed that the methanol extract contains alkaloids, flavonoids, saponins, and tannins as major components. Saponins and tannins were present in chloroform and n-hexane extracts; however, steroids and flavonoids were additionally found in n-hexane extract. Flavonoids, saponins, and tannins were present in aqueous extract of papaya flower. TLC and UV-visible spectroscopy also confirmed the presence of phenolics and flavonoids in different plant extracts. The total phenolic content (0.76 ± 0.04 mg GAE/g dry weight) and total flavonoid content (1.53 ± 0.10 mg QE/g dry weight) were the highest in the n-hexane extract of the flower. Antioxidant activity using DPPH free radical scavenging assay was the highest in n-hexane extract (64.07%). Antibacterial screening was carried out using well diffusion method against two pathogens Gram-negative bacteria Escherichia coli and Gram-positive bacteria Bacillus subtilis. The antibacterial assays of the extracts displayed the highest activity in methanolic extract against both E. coli (4.00 ± 0.08) and B. subtilis (01.00 ± 0.05). This is the first report for the presence of alkaloids and saponins in C. papaya flowers. Also, it is the first report for determination of total phenolics and total flavonoids in C. papaya flowers. Methanolic extract displayed considerable antibacterial activity against E. coli and B. subtilis. The antioxidant and antibacterial properties of phytochemical extracts make them attractive alternative complementary medicines. More chemical investigation for chemical constituents is important for further drug development programs.

中文翻译：

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番木瓜花的抗氧化、抗菌活性和植物化学特性

Carica papaya 是一种著名的药用植物，在世界各地用于治疗疟疾、登革热、炎症和皮肤感染等多种疾病。在这项研究中，使用不同的方法（如薄层色谱法和紫外光谱法）以及抗氧化和抗菌活性的评估，对木瓜花进行了初步的植物化学筛选。还开发了提取物的 TLC 和紫外-可见光谱分析方法。植物化学筛选结果表明，甲醇提取物含有生物碱、黄酮、皂苷和单宁作为主要成分。氯仿和正己烷提取物中存在皂苷和单宁；然而，在正己烷提取物中还发现了类固醇和类黄酮。黄酮类化合物、皂苷和单宁存在于木瓜花的水提物中。TLC 和紫外-可见光谱也证实了不同植物提取物中酚类和黄酮类化合物的存在。花的正己烷提取物中的总酚含量（0.76 ± 0.04 mg GAE/g 干重）和总黄酮含量（1.53 ± 0.10 mg QE/g 干重）最高。使用 DPPH 自由基清除试验的抗氧化活性在正己烷提取物中最高 (64.07%)。采用井扩散法对两种病原体革兰氏阴性菌大肠杆菌和革兰氏阳性菌枯草芽孢杆菌进行抗菌筛选。提取物的抗菌测定显示甲醇提取物对大肠杆菌 (4.00 ± 0.08) 和枯草芽孢杆菌 (01.00 ± 0.05) 的最高活性。这是关于木瓜花中存在生物碱和皂苷的第一份报告。还，首次报道了木瓜花中总酚和总黄酮含量的测定。甲醇提取物对大肠杆菌和枯草芽孢杆菌显示出相当大的抗菌活性。植物化学提取物的抗氧化和抗菌特性使其成为有吸引力的替代补充药物。对化学成分进行更多的化学研究对于进一步的药物开发计划很重要。